JP2545923B2 - Pulse motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to improvement of current-torque characteristics of a variable reluctance type (hereinafter referred to as VR type) pulse motor.

[Prior Art] FIG. 5 shows an example of current-generated torque characteristics of a conventional VR type pulse motor.

As shown in the figure, the generated torque T is proportional to the square of a current (hereinafter, referred to as a drive current) I flowing through a coil of a motor to generate torque, but magnetic saturation occurs in a large current region. The torque saturates and the characteristic curve deviates from the quadratic curve.

[Problems to be Solved by the Invention] In a motor having such a characteristic curve, the relationship between the generated torque T and the drive current I is non-linear, and when the drive current I is near zero, the slope of the curve is close to 0. There was a problem that it was difficult to control.

With a permanent magnet type pulse motor (PM type pulse motor) and a hybrid type pulse motor, the generated torque has the characteristic that the generated torque is proportional to the drive current.
There are problems that the material cost of the motor becomes high and the assembly is troublesome.

The present invention has been made to solve these problems at the same time, and an object thereof is to realize a pulse motor which uses a VR type pulse motor, in which the generated torque is proportional to the drive current and which is easy to control. .

[Means for Solving the Problems] The present invention provides a variable reluctance type pulse motor in which a torque generated from a salient pole is proportional to a square of a current flowing through a coil wound around the salient pole. The coils of the same phase are wound, and they are at positions facing each other, and the salient poles that form a pair by the salient poles whose teeth have the same phase, and the salient poles that form one pair are at different positions, A coil of the same phase as that of a salient pole that forms a pair is wound, and the teeth of the salient pole are offset by 1/2 pitch from the salient pole that forms a pair. I _A1 + I _{AB on the} pole and the coil wound around the pair of salient poles
(However, I _A1 is a drive current and I _AB is a bias current), a current proportional to (I _A1 + I _AB ) ² is generated from one pair of salient poles, and the other pair of salient poles is generated. A current I _A1 −I _{AB is} applied to the coil wound around the pole, and a torque proportional to − (I _A1 −I _AB ) ² is generated from the salient poles forming another pair,
And a current supply means for making the sum of the torque generated from one pair of salient poles and the torque generated from the other pair of salient poles proportional to 4 · I _A1 · I _AB. It is a pulse motor.

[Examples] The present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a main part of an embodiment of a pulse motor according to the present invention. This figure shows the structure of the stator core of an outer rotor type motor provided with 12 salient poles by three-phase excitation.

In this motor, 1 is a stator, and salient poles 2 ₁ to 2 ₄ , 3 ₁
~ 3 ₄ , 4 ₁ ~ 4 ₄ are formed. A coil is wound around each salient pole, and teeth 5 with a constant pitch are formed at the tips.
In the figure, stator teeth 2 ₁ and 2 ₂ coil ₆₁ wound with the _six-2, others are omitted. These coils, stator teeth ₂₁ to _24, 3 ₁ to 3
_4, comprise each one phase at ₄₁ to _4-wound coil.

In salient poles in which coils of the same phase are wound, the teeth of salient poles at opposite positions have the same phase, and the teeth of salient poles at different positions by 90 ° are out of phase by p / 2 (p is tooth 5 pitch).
For example, in the salient pole 2 ₁ and 2 ₂ of the teeth are the same phase, stator teeth 2 _1, 2 ₂ to the stator teeth 2 _3, 2 ₄ of the phase is shifted p / 2.

 The same applies to salient poles wound with coils of other phases.

Further, salient poles 21 _{to 24,} 3 ₁ to 3 _{4, 41} to ₄ tooth phase is shifted by p / 3.

From this, salient poles 2 ₁ and 2 ₂ , 2 ₃ and 2 ₄ , 3 ₁ and 3 ₂ ,
3 ₃ and 3 ₄ , 4 ₁ and 4 ₂ , 4 ₃ and 4 ₄ are A pole, A ′ pole, and B pole, respectively.
A pole, a B ′ pole, a C pole, and a C ′ pole.

Reference numeral 7 is a current supply means for supplying a current to the coil wound around the salient pole.

Salient poles facing each other in the same phase, for example salient poles 2 ₁ and 2 ₂
The coils wound on are wound in the same direction and are connected in series.

FIG. 2 is a view showing the tooth top shapes of the stator core and the rotor core and the relative positional relationship between them, and in this figure, the stator and the rotor are shown in an expanded manner.

FIG. 1 shows the coil wound around the A pole to show how to connect the coils, but in FIG. 2, the coil is wound around the A pole and the A ′ pole for convenience of explaining the operation of the motor. The coil is shown.

In FIG. 2, reference numeral 8 denotes a rotor having teeth 9 facing the teeth 5 and having the same pitch as the teeth.

With such a motor, at the relative tooth tip position shown in FIG. 2, the drive current I _A is caused to flow through the coil 6 ₁ wound around the salient pole 2 ₁ (this salient pole is referred to as the A pole), When the drive current I _A ′ is passed through the coil 6 ₄ wound around the pole 2 ₄ (this salient pole is referred to as the A ′ pole), the rotor 8 moves in the a direction at the A pole and the rotor 8 moves in the b direction at the A ′ pole. Generates torque to move each. The generated torques of the A pole and the A ′ pole are shown as g ₁ and g ₄ in FIG. The graph of FIG. 3 is a graph in which the vertical axis represents the generated torque T and the horizontal axis represents the drive current I.

Here, if the current flowing through the coil wound around the A pole and the A'pole is only the drive current I _A = I _A ', the A pole and the A'
The torques T ₁ and T ₄ generated by the poles are T ₁ ∝ (I _A ) ² and T ₄ ∝ (I _A ′) ² , and since the constants of proportionality are equal, T ₁ = T ₄ . Here, since the teeth of the A pole and A'pole are out of phase with each other by 1/2 pitch, the generated torques T ₁ and T ₄ are equal in magnitude and act in opposite directions. As a result, the sum T ₀ of the generated torques T ₁ and T ₄ becomes T ₀ = T ₁ −T ₄ = 0. Therefore, the motor does not rotate.

Therefore, in the motor according to the present invention, bias currents I _AB and I _AB ′ having the same magnitude as the currents flowing in the coils wound around the A pole and the A ′ pole are superimposed. Then, the drive current and the bias current are summed to the coil wound around the A pole, and the drive current and the bias current are differentially passed to the coil wound around the A ′ pole. Therefore, the currents I ₁ and I ₂ flowing in the coils wound around the A pole and the A ′ pole respectively become I ₁ = I _A1 + I _AB I ₂ = I _A1 ′ −I _AB ′. Here, I _A1 and I _A1 ′ are drive currents.

As a result, the torques T ₁ and T _{4 become} T ₁ ∝ (I _A1 + I _AB ) ² T ₄ ∝ (I _A1 ′ −I _AB ′) ² . As mentioned above, the poles of the A pole and A'pole have a half phase.
Since they are deviated by the pitch, the generated torques T ₁ and T ₄ act in opposite directions. Since the proportional constants are equal, the generated torque T ₁
The sum T _{0 of} T ₄ and T ₄ becomes T ₀ = T ₁ −T ₄ ∝ (I _A1 + I _AB ) ^2- (I _A1 ′ −I _AB ′) ² . Since the drive currents I _A1 and I _A1 ′ are equal and the bias currents I _AB and I _AB ′ are equal, T ₀ ∝4 · I _A1 · I _AB .

A graph of these relationships is shown in FIG.
In this figure, graphs f ₁ and f ₄ are graphs of generated torques T ₁ and T ₄ from the A pole and A ′ pole, respectively, and graph f ₀ is the generated torque T _0.
Is a graph of.

As shown in the graph, the generated torque T ₀ is _equal to the drive current I _A1
= I _A1 ′ = 0, the magnitudes of T ₁ and T ₄ are equal and they act in the opposite directions, and thus become 0. When I _A1 = I _A1 ′ ≠ 0,
The generated torque T ₀ becomes a proportional straight line in the current region where the torques T ₁ and T ₄ do not reach saturation (do not deviate from the quadratic curve).

The motor according to the present invention does not rotate when the same drive current I _{A is} applied to the coils wound around the A pole and the A ′ pole. A current I _A1 + I _{AB is applied} to the A pole and a current I _A1 −I _AB is applied to the A'pole.
The motor is rotated by causing the current to flow, and the generated torque T _{0 at} this time is proportional to the drive current I _A1 .

For the above reasons, in the present invention, the phases of the teeth of the A pole and A'pole are shifted by 1/2 pitch.

The above relationship was the relationship between the A pole and the A'pole, but other B
The same applies to the pole and B'pole and the C pole and C'pole.

In this way, if the current flowing in the coil is set to a predetermined condition,
The generated torque is proportional to the drive current.

It should be noted that in the embodiment, a three-phase excitation motor has been described, but the motor is not limited to this and may be two-phase excitation or other multi-phase excitation.

Further, in the embodiment, the case where the salient poles of two kinds of tooth phases are provided in one phase has been described. You may make it the structure which provided the salient pole of many kinds. However, the number of types of salient poles per phase must be the same for all phases.

[Effect] According to the present invention, since the generated torque is made proportional to the drive current by causing the bias current to flow through the salient pole coil, control of the motor becomes easy.

Further, while taking advantage of the advantages of the VR type pulse motor that the material cost is low and the assembly is easy, it is possible to obtain the proportional characteristics equivalent to those of the PM type pulse motor.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of an embodiment of a pulse motor according to the present invention, FIG. 2 is a development view of the motor of FIG. 1, and FIGS. 3 and 4 are operation explanatory diagrams of the motor of FIG. FIG. 5 is a torque-current characteristic diagram of a conventional pulse motor. 1 …… stator, 2 _{1 to} 2 ₄ , 3 _{1 to} 3 ₄ , 4 ₁ to 4 ₄ …… salient pole, 5,9
...... teeth, 6 _1, 6 _2, 6 ₄ ...... coil, 7 ...... current supply means, 8
...... Rotor.

Claims (1)

(57) [Claims] 1. A pulse motor of variable reluctance type, wherein the torque generated from the salient poles is proportional to the square of the current flowing through the coil wound on the salient poles. The salient poles that face each other and form a pair with salient poles that have the same phase of teeth, and the salient poles that form a pair and that are in a different position from the salient poles that form the pair. A coil of the same phase is wound, and the teeth of the salient poles are displaced by 1/2 pitch from the salient poles forming one pair, and the salient poles forming another pair by the salient poles, and the one pair I _A1 + I on the coil wound around the salient pole
_A current of _AB (however, I _A1 is a drive current and I _AB is a bias current) is made to flow, a torque proportional to (I _A1 + I _AB ) ² is generated from one pair of salient poles, and the other pair is formed. A current of I _A1 −I _{AB is} made to flow through the coil wound on the salient poles, and a torque proportional to − (I _A1 −I _AB ) ² is generated from the salient poles of the other pair, and the salient poles of one pair are generated. a pulse motor, characterized in that a current supply means for generating torque and torque proportional to the sum of the generated torque to 4 · I _A1 · I _AB from salient pole forming the other pair, equipped with a from.